Acute coronary syndromes are due to an acute or subacute primary reduction of myocardial oxygen supply provoked by disruption of an atherosclerotic plaque associated with inflammation, thrombosis, vasoconstriction and microembolization. Occlusive thrombosis superimposed on a ruptured atheroma in an epicardial coronary artery is firmly established as the immediate cause of an acute ST-segment Elevation Myocardial Infarction (STEMI). Rapid restoration of blood flow (oxygen supply) to jeopardized myocardium limits necrosis and reduces mortality. This can be accomplished medically with a thrombolytic agent, or mechanically, with so-called primary balloon angioplasty or stenting. Primary percutaneous coronary intervention (PCI) has become the preferred therapy for STEMI in most developed countries.